The present invention relates to a radio information terminal connectable to a portable personal computer.
Portable telephones are used widely and voice communication is now available at anytime and everywhere. On the other hand, the portable computer (PC) is made thinner, lighter and easier to carry, increasing the demand of online operation everywhere using radio data communication. To meet such demand, a radio information terminal has been commercialized, to function as a modem for performing the radio data communication, when the terminal is connected to a PC through a general use interface such as PCMCIA, and to function as portable telephone, when the terminal is disconnected from the PC.
Now, the PC is a man-operated terminal requiring a certain ergonomically determined volume and a place for online operation is restricted, in general, to the inside of a building or the like. On the other hand, as a radio wave hardly reaches into the building, it is difficult to achieve real time communication with the radio information terminal, as assured by a cable modem.
It is therefore an object of the present invention to facilitate online operation by a portable computer.
Other objects of the present invention will become clear as the description proceeds.
According to an aspect of the resent invention, there is provided an improved radio information terminal comprising: a radio unit, which when connected to a portable computer, functions as a proxy server to the portable computer under the condition that the radio unit is unable to receive a control radio wave from a base station, and synchronizes primary information received from the portable computer with secondary information of an original server received via the base station under the condition that the radio unit is able to receive the control radio wave from the base station.
The portable computer or an operation unit may be connected to the radio unit, and the radio unit functions as a portable telephone when the operation unit is connected to the radio unit.
The radio unit may be supplied with power from the portable computer when the portable computer is connected to the radio unit, and the radio unit may be supplied with power from the operation unit when the operation unit is connected to the radio unit.